Digital lighting technologies, i.e., illumination based on semiconductor light sources, such as light-emitting diodes (LEDs), offer a viable alternative to traditional fluorescent, HID, and incandescent lamps. Functional advantages and benefits of LEDs include high energy conversion and optical efficiency, durability, lower operating costs, and many others. Recent advances in LED technology have provided efficient and robust full-spectrum lighting sources that enable a variety of lighting effects in many applications. Some of the fixtures embodying these sources feature a lighting module, including one or more LEDs capable of producing different colors, e.g., red, green, and blue, as well as a processor for independently controlling the output of the LEDs in order to generate a variety of colors and color-changing lighting effects, for example, as discussed in detail in U.S. Pat. Nos. 6,016,038 and 6,211,626, which are hereby incorporated by reference.
In various conventional LED lighting fixtures, an onboard microprocessor must determine the requested brightness of light output by the LED light source by measuring dimming information provided by a dimmer. For example, dimming angle may be measured and used as an indicator of the requested brightness. However, the output of the dimmer may vary from one phase to the next, causing the input to the microprocessor to be noisy. When the input to the microprocessor is mapped directly to the brightness of the LED lighting fixture, the output light visibly flickers.
Thus, there is a need in the art for efficiently controlling the light output by an LED lighting fixture in response to changes in dimming angle, to enable smooth transitions among dimming levels, with no visible flicker or other negative effects.